Pluid actuated percussive tool



rJune 2, 1931. F. A. .uMERsoN 1,807,787

FLUID AGTUATED PERCUSSIVE TOOL Filed Oct. ll. 1928 lzyI/ENTOR. o .Jz'menfon.

BY fl/.5' ATToRNEx 7 fusi-2F y W Y/ fr? f if j M Patented June 2, 1931 UNITED STATES PATENT OFFICE FRANCIS A. JIMERSON, OF ATHENS, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RAND COMPANY, OF JERSEY CITY, NEVI JERSEY, A CORPGRATON OF NEW JERSEY FLUID ACTUATED PERCUSSIVE TOOL Application led October 11, 1928.

This invention relates to lluid actuated percussive tools, but more particularly to a valve action for the type of tool known as semi-valveless in which the admission of pressure fluid to the rear end of the cylinder is controlled by a fluid actuated valve while the admission of fluid for driving the piston rearwardly is controlled by the piston.

The obj ects oi the present invention are to obtain an inlet valve which is quick and positive in actionv and which will increase the speed of the piston travel and be sensitive to, and effectively controlled by pressure fluid.

Another object is to construct a valve which will permit the exhaust of pressure iluid from the rear end or" the cylinder through the valve and thus increase the efficiency o' the tool.

Other objects of the invention will hereinafter appear and to all of these ends the inventionis shown in the accompanying drawings7 in which;

Figure 1 is a longitudinal cross sectional view of so much of a pneumatic tool as will show the piston and valve in their rearmost positions and Figure 2 is a view similar to Figure 1 showing the piston and the valve in their forwardmost positions.

Referring more particularly to the drawings A is the cylinder of a pneumatic tool having a hammer piston B. The piston B has a reduced forward extension C adapted to lit slidably inthe correspondingly reduced portion D or' the cylinder A. The forward end of the cylinder is closed by a front cylinder washer E bored to receive the shank F of a working implement (not shown). A back head Gr forms a closure for the rearward end of the cylinder and interposed between the back head G and the .cylinder A isla plate H. v

The back head G is bored longitudinally to receive a valve bushing J. A transverse slot K is adapted to receive a yoke bar L which forms part of the handle fastening mechanism which will notbe described since it forms no part of this invention. A valve O lits -slidably in the valve bushing J and acts as a semi-automatic throttle valve for the tool. The operation of the valve O is coop- Serial No. 311,775.

erative with the handle P; that is when the workman pushes downwardly upon the handle P the valve O is forced down against the upward force of the pressure fluid in the small chamber Q, in the valve bushing J.y A leak port R constantly admits pressure fluid to the chamber Q from the hose S and when the workman presses downward upon the handle P the valve 0 moves downward bringing a ring grooveY T on the valve O into such a position that pressure fluid may pass freely from the hose into a passage U. l/Vhen pressure is released from the handle the pressure fluid in the chamber Q forces the valve upward thus throwing the ring groove out of connection with the passage U and the hose S. A sliding fit i-s maintained between a sleeve V on the handle P and the back head Gr. This type of handle construction is 'fully described in the patent to F. A. J imerson No. 1,160,617. Y

A valve chamber W is formed in the forward end of the back head G and a valve X is mounted therein. The valve X is of substantially cylindrical shape and a ring groove Y is formed intermediate its ends. A passage Z is formed transversely through the valve and this passage has its ends in the ring groove Y. A short longitudinal passage Z) connects the passage Z with the forward face of the valve X. An annular groove c is formed within the valve chamber W and a second annular groove d formed partly in the back head G and partly in the plate H permits communication between the passage U and the valve chamber W. A leak port c leads from the groove c to atmosphere. A short passage f formed in the plate H affords communication between the chest W and the rearward end or the cylindervA.

The ports and passages not yet mentioned may be more easily described in connection with the operation of the tool, which is as follows:

Assuming the movable parts of the tool to be in the position shown in Figure 1 liv-e air vis admitted through the throttle valve and having forced the valve upward by pressure l exerted on the exposed lower face g which projects into the chamber d. Pressure fluid t-hen passes through the port and into the cylinder A. behind the piston B forcing the piston forward on its working stroke. As the piston advances the strixing end B closes a port 7iy and ring grooves and 7c in the striking ent l successively admit pressure fluid from a passage Q into a port 0 which opens into a passage y) in the cylinder A. The pressure fluid thus admitted to the passage j) will travel up to the rear end of the valve X, filling the chamber Vif and forcing the valve down onto its front seat. rihe closing of the valve will take place regardless of the fact that the area beneath the valve exposed to fluid pressure is greater than the initial area exposed to -fluid pressure on the top of the valve; for the pressure under the valve is less than full line pressure due to the forward movement `of the piston, whereas the pressure on the upper surface is substantially full line pressure. Upon continuing its forward motion the piston will uncover an exhaust port r permitting the rearward end of the cylindeil to exhaust to the atmosphere. At the same time a ring groove s in the striking end B ofthe piston connects the passage Q with a chamber t permitting live pressure lfluid to act against a shoulder u on the piston The piston will then start on its return stroke and after the exhaust port 7 is closed the compression is relieved through the passages z, Z), Z and e.

The valve X will ren'iai-n closed until the striking end oil the piston uncovers port Je, whereuponpressure on the rear end of the valve vwill be relieved due to the fact that a chamber i', formed in the lower end of the Vcylinder el., will exhaust to the atmosphere by way of av passage ui, ring grooves's and exhaust ports fr and r. The cycle of operations is started by the lifting of the valve X.

In'practice the device above described is quick and positive in action and economical in the consumption lof pressure fluid.

I claim:

l. In a fluid actuated percussive tool, the combination of a cylinder having a reciprocating piston and an exhaust port located intermediate the ends of the cylinder, a valve vchest and a fluid actuated inlet valve having `a ring groove around its central portion, -a port passing transversely through the'valve and communicating at both ends with said ring groove, a longitudinal port communicating with the front end of said valve and with the said transverse port, a passage leading through the wall of the cylinder fromaii annular `groeve in said valve chest, said Iannular groove being adapted to cooperate with the ring groove and the longitudinal passage in said valve for relieving compression'from the rearward end of the cylinder, a passage communicating with the valve chest Leonie? and with the rearward end of said cylinder, a second passage communicating with the valve chest and with the cylinder at a point between the front end of the cylinder and the exhaust port, said first passage being controlled by said valve and .admitting pressure fluid to the/rear end ofthe cylinder, said second passage being controlled by the piston and admitting pressure fluid to the front end of' the cylinder,a third passage in said cylinder leading from the front end of the cylinder to the rearward end of said valve chest, grooves in said piston providing communica- `tionbetween said second passage and said third passage for carrying pressure fluid to the rear'eiid of said valve chest to throw-said valveforwardly to vclose the passage leading from tlievalve chest to the rearward-end of the cylinder.

i2. ln a fluid actuated percussive tool, the combination of a cylinder anda reciprocable piston, a ina-iii exhaust yport controlled by the piston for exhausting thecylinder from both Vends of the piston, a valve chesthaving a valve chamber, an inlet passage lleading from one end of the-valve chamber to the rear yend uof the cylinder, a supply cha-nibervat the saine end of the valve'chambcr and in constant communicationavith a source of pressure fluid supply, a reciprocatory valve in .thcvalve chamber actuated in one direction by the pressure fluid in said supply chamber fuit pressure fluid therefrom to the finlet passage, an auxiliary eX-haust port i-n the 'carve chest,.passages Yin the valve yadapted to register with said auxiliary exhaust porta-n d the iii-let passage to relieve compression from the rear end of the cylinder, =a second inlet passagecontrolled bythe piston for `intermittently supplying pressure fluid to the front 'end .et the cylinder, and a passage controlled by the piston for intermittently supplying pressure iuid to the opposite end of the valve chamber `to return the valve.

In a'fluid actuated percussive tool,` the combination of a cylinder having a piston chamber and a reduced bore, a diii'erential piston reciprocable in the piston chamber :and the reduced bore,;anexhaust port inthe piston chamber controlled by the'piston,` a valve chest having a valve chamber, an inlet passage yleading from one end of the valve chamber to the rear end :of the cylinder, :a isupplychamber opening into the same end of the valvecliainber and in constant communication with a source of pressure fiuid supply,

a valve in the 'valve chamber` controlling communication between the supply chamber'and the inlet passage, a second inlet passage leading from: the supply chamber to the reduced Ibore, a groove in the piston adapted to register with said inlet passage and the front end of the cylinder, .a passage leadingfroni the reduced bore to the .opposite end of the valve chamber, and ,a second groovezin the piston forwardly of the first said groove for establishing communication between the second inlet passage and the last said passage to actuate the valve to the closed posltion.

4. In a fluid actuated percussive tool, the combination of a cylinder and a reciprocable piston, an exhaust port in the cylinder controlled by the piston, a valve chest having a valve chamber, an inlet passage leading from one end of the valve chamber to the rear end of the cylinder, a supply chamber opening into the same end of the valve chamber as the inlet passage and being in constant communication With a source of pressure fluid supply, a reciprocatory valve in the valve chamber actuated in one direction by the pressure fluid in the supply chamber to admit the pressure fluid therefrom to the inlet passage, a second inlet passage controlled by the piston for intermittently supplying pressure fluid to the front end of the cylinder, and a passage controlled by the piston for intermittently supplying pressure Huid from the front end of the cylinder to the opposite end of the valve chamber to return the valve.

5. In a Huid actuated percussive tool, theV combination of a cylinder and a reoiprocable piston, an inlet passage controlled by the piston for supplying motive fluid to the front end of the cylinder, a valve chest having a valve chamber, a second inlet passage leading from one end of the valve chamber to the rear end of the cylinder, a valve in the valve chamber movable to one position to admit motive fluid through the second inlet passage to the rear end of the cylinder, said motive fiuid holding the valve in said posi-tion, and a passage controlled by the piston for intermittently supplying motive fluid from the front end of the cylinder to the valve chamber to act in opposition to the motive fiuid holding the valve in said position and thereby return the valve. Y

In testimony whereof I have signed this specification.

FRANCIS A. JIMERSON. 

